An important issue to neurobiologists is whether neurons of the adult central nervous system (CNS) are capable of regenerating or regrowing into functional nervous tissue. These capabilities are critical for efforts to repair the CNS. Studies of some birds have revealed that steroid hormones can have significant effects on the brain, including playing a role in neuronal restructuring (plasticity) in adults. While there is limited evidence for plasticity in the mammalian spinal cord, nothing is known about steroid actions, including effects on neural plasticity, in the avian spinal cord. Dr. Schlinger has identified an avian model (the Golden-collared manakin of Panama) that appears to have a steroid-sensitive neuromuscular system centered in the spinal cord. In pilot studies, he found that many neurons in the male manakin spinal cord accumulate androgens and also identified one wing muscle that is sexually dimorphic in size. These observations suggest that androgens may act on both the spinal cord and musculature of these birds. Dr. Schlinger proposes to determine the full extent of the steroid sensitivity and sexual dimorphism of neural and muscular structures of these birds and evaluate whether androgens influence their growth and function. These studies will advance the understanding about steroid control of complex behaviors, including spinal cord sexual differentiation and neural plasticity.
